Expandable mandrel

ABSTRACT

The invention relates to a mandrel which is expandable and retractable within definite limits to predetermined diametral sizes and is capable of being disposed upon a central support shaft. The mandrel includes a support tube having a series of longitudinally aligned wedging rings concentrically disposed about said tube, said wedging rings having recesses for accommodating radially expandable cylindrical wedges. Each of the wedging rings is provided with an abutment at one end for engaging the wedges and arresting the innermost limit of travel. Furthermore, the abutments are designed to engage the next adjacent wedging ring, thereby limiting the outermost limit of travel of the wedges. In addition, the support tube is shiftable along the central support shaft by means of a crank handle so that any package formed on the mandrel can easily be removed therefrom.

lllnlllle lltnrlnnn Patent [54] EXPANDABUE MANDREIL [72] Inventor:

[73] Assignee: Goldsworthy Engineering, Inc. [22] Filed: Aug. 1, I969 [21] Appl. No.: 846,789

Harald E. Karlson, Santa Monica, Calif.

[ 1 Feb. 29, 11.972

Primary Examiner-George F. Mautz Assistant Examiner-Gregory A. Walters ABSTRACT The invention relates to a mandrel which is expandable and retractable within definite limits to predetermined diametral sizes and is capable of being disposed upon a central support shaft. The mandrel includes a support tube having a series of longitudinally aligned wedging rings concentrically disposed about said tube, said wedging rings having recesses for accommodating radially expandable cylindrical wedges. Each of the wedging rings is provided with an abutment at one end for engaging the wedges and arresting the innermost limit of travel. Furthermore, the abutments are designed to engage the next adjacent wedging ring, thereby limiting the outermost limit of travel of the wedges. In addition, the support tube is shiftable along the central support shaft by means of a crank handle so that any package formed on the mandrel can easily be removed therefrom.

6 (Ilairns, 9 Drawing Figures Patented Feb. 29, 1972 2 Sheets-Sheet 2 FIG.8

INVENTOR HARALD E. KARLSON AT TORNIEY IEXPANIIABLE MANIDRIEL The invention relates in general to certain new and useful improvements in expandable mandrels, and more particularly, to a mandrel which is capable of being both expanded and retracted to definite diametral sizes.

Today, there are a number of commercially available expandable mandrels which are capable of use in a wide variety of applications. Some of these mandrels are flexible and are capable of being inflated, either pneumatically or hydraulically. There are other mechanically actuated mandrels which consist of alternately opposed wedges. These mandrels operate in such manner that when the wedges are urged toward each other, they will shift radially outward to cause the diametral size of a sleeve disposed therearound to expand diametrally. When the wedges of these mechanically actuated mandrels are disengaged, the wedges will shift radially inward enabling the sleeve disposed therearound to achieve a reduced diametral size and thereby reducing the overall diametral size of the mandrel. However, in all of these commercially available mandrels, there is no mechanism for regulating the maximum and minimum diametral size during expansion and retraction. Consequently, the presently available mandrels are not sufficiently accurate for use in many applications, such as filament winding where a finally formed product on the mandrel must have a definite inner diametral size.

It is, therefore, the primary object of the present invention to provide an expandable mandrel which is capable of being expanded to an exact outer diametral size and being retracted to a definite inner diametral size.

It is another object of the present invention to provide an expandable mandrel of the type stated which is easy to operate and highly efficient in its operation.

It is a further object of the present invention to provide an expandable mandrel of the type stated which is highly reliable and relatively inexpensive to manufacture.

It is an additional object of the present invention to provide a mandrel of the type stated which is completely mechanical in its operation and, therefore, avoids the nonlinearities incurred with pneumatically expandable mandrels.

With the above and other objects in view, my invention resides in the novel features of form, construction, arrangement and combination of parts presently described and pointed out in the claims.

In the accompanying drawings (2 sheets):

FIG. I is a side elevational view, partially broken away and in section, of an expandable mandrel constructed in ac cordance with and embodying the present invention;

FIG. 2 is a fragmentary sectional view taken along line 2-2 of FIG. I;

FIG. 3 is an enlarged vertical sectional view showing a portion of the handle mechanism forming part of the mandrel of FIG. I;

FIG. 4 is a vertical sectional view taken along line 4-4 of FIG. I;

FIG. 5 is a fragmentary sectional view taken along line 5-5 of FIG. 4;

FIG. 6 is a vertical sectional view taken along line 66 of FIG. 3;

FIG. 7 is a fragmentary sectional view taken along line 7-7 of FIG. 6; and

FIGS. 8 and 9 are fragmentary sectional views taken along lines fI-d and 9-9 respectively of FIG. 2.

Referring now in more detail and by reference characters to the drawings which illustrate a preferred embodiment of the present invention, A designates an expandable mandrel which is mounted on a support shaft S. The support shaft S may form part of any fixed apparatus such as a mandrel support shaft fixed to a specific piece of equipment. For example, the expandable mandrel of the present invention would find effective use in spool winding apparatus, devices for producing filament reinforced tubular members and the like. In spool winding apparatus, the filament strands are typically wound upon the mandrel in order to form a roving package. It is necessary to have a fairly exact inner diametral size of the roving package produced after the same has been wound upon the mandrel. Accordingly, mandrels of the type illustrated and described herein have been found to beparticularly effective on apparatus used in the formation of roving spools.

The mandrel A generally comprises a support tube 1 which is preferably formed of steel or other structural material and is sized to be concentrically disposed about the support shaft S. The support shaft S is turned down at one transverse end in the provision of a diametrically reduced section 2 having an exterior annular wall 3 and an annular shoulder 4 at its lefthand end, reference being made to FIG. I. Shiftably disposed upon the diametrally reduced section 2 is the support tube I.

By further reference to FIG. I, it can be seen that the sup port tube I is provided with an annular exterior surface 5 which integrally merges at its left-hand end into an enlarged boss 6. The boss 6 is provided with an annular abutment wall 7 which engages the shoulder 4.

Concentrically disposed about and being rigidly fixed to the boss 6 is a sleeve 8 which has a tapered end wall or so-called wedging end wall 9. Furthermore, it can be seen that the sup port tube I is shiftable along the annular surface 5 of the support shaft S from an inner position as illustrated in FIG. I to an outer or unloading position as illustrated in FIG. 3.

Circumferentially disposed about the support tube 1 are a series of axially aligned wedging sleeves 10 having arcuate bottom walls II which engage the exterior surface of the support tube ll. Each of the wedging sleeves 10 is provided with a relatively flat right end wall I2 which merges into a tapered wedging wall I3. At the left-hand end, each of the wedging sleeves I0 is provided with relatively flat left end walls 14 and integrally formed extended lips 15 which are sized to engage the right-hand end wall of the next adjacent wedging sleeve I0 in the manner as illustrated in FIG. 1. The extended lip 15 is provided with an outer surface I6 engageable against the right end wall I2 of the next adjacent wedging sleeve I0 and an upper abutment-forming surface 17.

By reference to FIG. I, it can be seen that when two wedging sleeves III are abutted against each other that a wedging recess I8 has been formed. Shiftahly disposed within each of the wedging recesses I8 are wedging rings or so-called camming rings 19 which have camming surfaces 20 conformable to and engageable against the wedging walls I3 of each of the wedging sleeves 10. In addition, the wedging rings I9 which are more fully illustrated in FIGS. 5 and 7-9 have a relatively flat annular exterior surface 21 and a flat right end wall 21 which is engageable against the left end wall Id of the next adjacent wedging sleeve It). By further reference to FIG. 2, it can be seen that the uppermost wedging ring I9 is disposed in camming relationship with the wedging wall 9 of the fixed sleeve 3. By reference to FIGS. 5 and 6, it can be seen that the wedging rings I9 are provided with alternating slits 23 extending from the inner annular surface and the ex terior annular surface. In addition, thezring I9 is provided with one slit 24 which extends through the body thereof to form a gap with a pair of opposed margins. Theseslits 23 and 24 provide sufficient flexibility enabling the ring to expand and retract its diametral size in response to pressures imposed thereon.

Thus, it can be seen that when each of the wedging sleeves I0 is permitted to be shifted axially apart, each of the camming rings I9 will shift downwardly in the wedging recesses 18. As this occurs, the lower or inner'annular surface of the camming rings I9 will engage the abutment forming surface 17 thereby limiting the inner limit of travel, and hence, defining thesmallest diametral size the camming rings I9 can assume. It can also be seen that even if further inwardly directed pressures were applied to each of the camming rings I9, their innermost limit of travel is regulated by the abutment forming surface I7. When each of the wedging sleeves I0 is shifted axially together, the annular lips 15 will engage the right end wall I2 of the next adjacent wedging sleeve 10. Furthermore, as each of the wedging sleeves I0 is axially compressed, the wedging wall 13 bearing against the camming surface 20 will force each of the camming rings radially outward in the manner as illustrated in FIG. 5. It can also be seen that this expansion or outer shifting movement is limited by the lip 17 on each of the sleeves 10. Accordingly, each of the camming rings has a very definite and specific outermost limit of travel upon expansion of the mandrel and a very definite and specific innermost limit of travel upon retraction of the mandrel.

Concentrically disposed about the aforementioned assembly is an outer sleeve 25, preferably formed of stainless steel and which engages the exterior annular surface 21 of each of the wedging rings 19. The sleeve 25 is provided with a longitudinal slit 26 and overhanging margins 27. By means of this construction, the outer sleeve 25 will also be permitted to expand when the mandrel is expanded. When the mandrel is retracted, the sleeve 25 will also retract in diametral size by the spring action of the metal. forming the sleeve 25. An upstanding pin 28 formed on the fixed sleeve 8 extends through a matching aperture on the sleeve 25 to prevent rotation or unauthorized axial movement of the latter.

The support shaft S is formed with a central bore and mounted on the interior surface thereof is a nut 30 having interior helical threads 31 which match a mating thread 32 on a locking screw 33. By reference to FIG. 3, it can be seen that the screw 33 is mounted on an extended stub shaft 34 fitted within a collar 35, which is in turn integrally formed with a cap member 36, the latter being disposed over the outer end of the support tube 1. The stub shaft 34 extends outwardly of the cap member 36 and rigidly keyed to the shaft 34 is a mounting plate 37 for retaining a pivotal handle 38. The handle 38 is pivotally mounted on the plate 37 and causes rotation of the stub shaft 34 by means of a pintle 39 extending through the plate 37 and the stub shaft 34. By means of this construction, the handle 38 is pivotal on the stub shaft 34 and is also capable of causing rotation of the stub shaft 34.

It can be seen that when the handle 38 is turned, it will enable the wedging sleeve to expand axially along the support tube 1, thereby enabling the camming rings 19 and hence the outer sleeve 25 to become reduced in the radial dimension. This action will cause the nut 30 to become disengaged from the threads 32 on the locking screw 33, thereby permitting shiftable movement to the right of the entire support tube 1 in the manner as illustrated in FIG. 3. Furthermore, this outer limit of travel is regulated by means of an upstanding pin 40 which is secured to the nut 30 and is movable in an elongated slot 41 formed in the support tube 1. When the pin 40 engages the left-hand end of the slot 41, the outermost limit of travel of the support tube 1 and the assembly carried thereon has been achieved. In like manner, when the abutment wall 7 engages the shoulder 4, the innermost limit of travel of the support tube 1 and the assembly thereon has been achieved.

The cap member 36 also carries a pair of diametrally opposed radially extending pins 43 which are movable in slots 44 formed in the cap member 36. In this manner, the cap is retained on the support tube 1 when the latter is shifted outwardly along the support shaft S. When the entire assembly is shifted inwardly as illustrated in FIG. 2, the cap member 36 will bear against the outermost camming ring 19 causing a compression type of action among each of the wedging sleeves 10. It can be seen that as the handle 38 is turned, the cap member 36 will cause each of the wedging sleeves 10 to axially compress and to force each of the camming rings 19 to expand radially. The camming rings 19 are urged outwardly against the inner surface of the sleeve 25 causing the latter to increase in diametral size.

It should be understood that changes and modifications in the form, construction, arrangement and combination of parts presently described and pointed out may be made and substituted for those herein shown without departing from the nature and principle of my invention.

What is claimed is: 1. An expandable mandrel comprising a first tubular member, a plurality of abutable sleeves disposed about said tubular member, a wedging recess formed by at least two of said sleeves, each of said sleeves having opposed camming faces defining said recess, a radially shiftable camming member disposed in said recess and having mating faces engageable with said camming faces, abutment means extending from one of said sleeves and toward the other of said sleeves to prevent said camming faces from engaging each other and limiting the outermost radial movement of said camming member, and a second tubular member disposed about said camming member.

2, The expandable mandrel of claim 1 further characterized in that said second tubular member has a variable diametral size conformable to movement of said camming member.

3. The expandable mandrel of claim 1 further characterized in that a plurality of recesses are provided and a shiftable camming member is disposed in each of said recesses.

4. The expandable mandrel of claim 3 further characterized in that means is provided for axially shifting said sleeves and camming members with respect to said first tubular member.

5. The expandable mandrel of claim 3 further characterized in that first gear means is located on the interior of said first tubular member, second gear means is engageable with said first gear means, handle forming means operatively connected to said second gear means and actuating same, and means operatively connecting said first gear means and sleeves to cause radial shifting movement of said camming members in 

1. An expandable mandrel comprising a first tubular member, a plurality of abutable sleeves disposed about said tubular member, a wedging recess formed by at least two of said sleeves, each of said sleeves having opposed camming faces defining said recess, a radially shiftable camming member disposed in said recess and having mating faces engageable with said camming faces, abutment means extending from one of said sleeves and toward the other of said sleeves to prevent said camming faces from engaging each other and limiting the outermost radial movement of said camming member, and a second tubular member disposed about said camming member.
 2. The expandable mandrel of claim 1 further characterized in that said second tubular member has a variable diametral size conformable to movement of said camming member.
 3. The expandable mandrel of claim 1 further characterized in that a plurality of recesses are provided and a shiftable camming member is disposed in each of said recesses.
 4. The expandable mandrel of claim 3 further characterized in that means is provided for axially shifting said sleeves and camming members with respect to said first tubular member.
 5. The expandable mandrel of claim 3 further characterized in that first gear means is located on the interior of said first tubular member, second gear means is engageable with said first gear means, handle forming means operatively connected to said second gear means and actuating same, and means operatively connecting said first gear means and sleeves to cause radial shifting movement of said camming members in response to said movement of said handle forming means.
 6. The expandable mandrel of claim 5 further characterized in that said second gear means is disengageable from said first gear means. 